table. They are fixed in the centre of the swivelling table, and
will transmit the feed motion with steadiness, even when the
table is swivelled up to 45°, say for cutting spiral mills, twist
drills, &c. By moving the hand lever y the mitre wheel w may
be drawn out of gear, and the cross feed given by hand, if
desired, a catch z ensuring the contact of the wheels when in gear.
The longitudinal feed from screw a is rather a setting motion,
there being few cases where other tban a cross feed is desired.
The handle b is to raise or lower the table, which it does by
turning the screw e through the medium of the worm gear d.
Other forms of machine are Vertical Milling Machines and
Profiling Machines. In the former the cutter spindle is vertical,
and a circular feed, as well as traverse, is given to the table. The
latter is a smaller tool, where a vertical mill is traversed by a hand
lever so as to accommodate itself to intricate forms. Good lubrica-,
tion is necessary for all mills, and should be supplied under pressure
from a small pump. (See also pp. 752, 811, 1020, and 1025.)
Dividing Head. — When milling teeth of wheels, cutters, rimers,
&c., the work is supported in centres shewn in Fig. 189, which
are fastened to a small bed and bolted to the machine table.
The wheel to be cut is fixed on a mandrel, and held in position